1. Field of Invention
The present invention relates to a fastening structure of a container, and more particularly, to a self-locking fastening structure of a clean container applied in a clean room.
2. Related Art
To clean containers, such as mask storage boxes, reticle storage boxes, wafer storage boxes, or glass substrate storage boxes, masks, reticles, wafers, or glass substrates are usually placed therein, so as to meet the strigent requirements on an ultra-clean storage environment for accommodating the masks, reticles, wafers, or glass substrates used in a semiconductor or a flat panel display process, and to strictly prevent the masks, reticles, wafers, or glass substrates from being contaminated by particles and affected by electrostatic charges and electrostatic fields. Currently, the semiconductor process requires Class 1 or better than Class 1 environment. Therefore, in a common semiconductor manufacturing fab. or flat panel display manufacturing plant, the masks, reticles, wafers, or glass substrates must be processed in an ultra-clean environment. The clean containers are used to transfer, load and unload, and store the masks, reticles, wafers, or glass substrates during a semiconductor process or a flat panel display process, so as to ensure that the masks, reticles, wafers, or glass substrates are in an environment meeting the ultra-clean process requirements.
A reticle box is taken as an example below. FIG. 1A is an exploded isometric view of a reticle box in U.S. Patent Publication No. 2004/0004704. The reticle box 10 includes a base 11 and a top cover 12 covered on the base 11. A groove 122 is formed in each of two opposite side faces 121 of the top cover 12, and an elastic piece 13 is accommodated in each of the grooves 122. Each of the elastic pieces 13 includes two elastic arms 131, and a flange 133 protrudes on a front part of each of the elastic arms 131, which can be engaged into a lateral groove 111 formed in the base 11, so as to fasten the top cover 12 on the base 11.
However, the conventional elastic pieces 13 are received in the grooves 122 respectively, and in order to prevent the elastic pieces 13 from dropping out, additional retaining plates 14 must be disposed to fix the elastic pieces 13 in the grooves 122. However, according to this design, because the force arm of the elastic arms 131 are long, and the torque endured by supporting points is large, when the elastic arm 131 is opened and closed repeatedly, and is easily broken or bent due to fatigue, thereby losing the function, the elastic pieces 13 must be replaced as a whole. Furthermore, each of the elastic pieces 13 needs a retaining plate 14 to prevent it from dropping out. As a result, not only the particles will easily deposit in the dead angles between the elastic pieces 13 and the retaining plates 14, but also the operation of cleansing and drying the reticle box 10 cannot be performed smoothly.
In addition, FIG. 1B shows another reticle box according to another prior art, and FIG. 1C is a partial enlarged view of Part A in FIG. 1B. In this prior art, a metal spring 16 provides a thrust force to fasten a fastener member 15, and a metal cover plate 17 is further provided, so as to not only support the spindle rotation of the fastener member 15, but also prevent relevant fastening components from dropping out. The metal spring 16 and the metal cover plate 17 may have rust and generate metal particles when contacting acidic/alkaline gases and DI Water. Similar to the prior art shown in FIG. 1A, not only the particles will easily deposit in the dead angles between the fastening member and the metal cover plate, but also the operation of cleansing and drying the reticle box cannot be performed smoothly. Moreover, in this prior art, the number of the parts will also be increased (14 parts are used in the fastener mechanism in total), so this prior art is not so perfect.